1. Field of the Disclosure
This disclosure generally relates to reclosable plastic bags, and a method of their manufacture that is more efficient and economical than conventional methods and devices. The present disclosure also relates generally to a continuous supply of preformed reclosable fasteners used in an apparatus for attaching a reclosable fastener to a flexible web of material. More particularly, the supply of preformed fasteners of this disclosure may be operatively attached to a conventional form, fill, seal and separate packaging machine in a manner that enables the packaging machine to produce high quality reclosable packages without interfering with the ordinary operation of the packaging machine, using the apparatus of the above-referenced co-pending application.
2. Description of the Prior Art
Reclosable containers utilizing zipper-type fasteners are well known in the packaging industry and are used for holding, displaying and dispensing a wide variety of products ranging from hardware items to food products intended for human consumption. With the increasing consumer preference for reclosable zipper-type plastic bags, there have been continual efforts to develop packaging machines for producing such is reclosable packages. This is especially true at the retail level for the sale of prepackaged convenience items such as, for example, food products.
As is also well known in the field of flexible packaging, there presently exist numerous machines for automatically forming, filling and sealing materials in flexible containers. As a result of consumer enthusiasm toward reclosable plastic containers, the packaging industry has sought to develop packaging machines for automatically forming, filling and sealing such reclosable containers. For example, U.S. Pat. No. 5,036,643 discloses a form, fill, seal and separate packaging machine with a means to apply a reclosable zipper to a web of material. However, the means for applying the zipper-type closure to the flexible web is incorporated within the packaging machine. Manufacturers currently utilizing conventional packaging machines are often unable to justify the costs involved with replacing existing machines with one such as disclosed in that '643 patent.
It is, therefore, clear that there remains a great need in the art for a suitable apparatus for attaching a zipper-type closure to a flexible material in a fashion that is particularly adapted to cooperate with existing conventional packaging machines, thus eliminating the requirement for total replacement of present-day packaging machines. In addition, such an apparatus should be capable of adjustment in order to accommodate the manufacture of reclosable packages of various sizes and weight content. Furthermore, such an apparatus should operate in a fashion so that it will not significantly affect the ordinary operation and installation of conventional form, fill, seal and separate packaging machines to which the apparatus would be attached.
Just as apparent is the need for a supply of reclosable fasteners suitable for use in such an apparatus. Such a supply must provide fasteners to the apparatus in a manner so that the fasteners may be efficiently and properly attached to permit forming a secure and reliable reclosable package.
One type of reclosable bag for use as such a reclosable package is illustrated in U.S. Pat. No. 5,461,845 to Yeager (“Yeager '845 patent”). There are at least two definitive shortcomings with the technology described therein. The first shortcoming relates to the problem of having to open the zipper completely from the front panel of the finished bag. Users of reclosable bags and packaging are accustomed to opening the profiled fastener from the “top” of the package, and not from the front panel of the package. Hence, the user will have to become accustomed to an unfamiliar or uncomfortable manner in which to open a bag.
The second shortcoming is more serious, and relates to the requirement of opening the package from the front panel thereof. If the package is to be opened from the front panel, a cut or perforation must be made before the fastener is applied. This cut, or perforation, is generally shaped like an “oval” with opening “tabs” for gaining access to the fastener. Since the fastener, most likely, is not closed at the ends of the fastener, the possibility of contamination exists.
The most expedient and economical way to make the package is to create the cut, or perforation, in one operation, just upstream of the fastener strip application. This operation, in its simplest form, will leave openings for potential contamination to pass through the cut or perforated front panel opening. To overcome this contamination potential, users of this method add a great deal more cost and complexity to create a sealed, sealable “patch”, or some other means of eliminating this contamination risk. The same problem occurs, if the package must be hermetically sealed.
Another example of the prior art includes U.S. Pat. No. 4,909,017 to McMahon (“McMahon '017 patent”). A particular problem with the McMahon '017 technique is that one obtains a naturally curled thin strip fastener that ultimately makes the fastener unstable, and irregularly shaped. In addition to the problem of sealing the backside of this unstable, irregular-shaped strip fastener to the bag wall(s), there is the problem of keeping the material from naturally curling after sealing the strip to a bag wall, making it even more difficult to get a uniform seal on the backside of the fastener strip.
Hence, there exists a need to solve the problems in the art that are articulated above.